Synthesis and magnetic properties of novel copper(II)-lanthanoid(III) heterobinuclear oxamido bridged complexes

Seven novel μ-oxamido hetero-metal binuclear complexes have been prepared and characterized, namely [Cu(oxae)-Ln(NO2-phen)2 (ClO4)](ClO4)2, where oxae denotes the N,N′-bis(2-aminoethyl)oxamido dianion, NO2-phen denotes 5-nitro-1,10-phenanthroline and Ln is Nd, Eu, Gd, Tb, Dy, Ho or Er. The magnetic susceptibility of [Cu(oxae)Gd(NO2-phen)2(ClO4)](ClO4)2 was measured over a 4–300 K temperature range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator Ĥ = -2JŜ1·Ŝ2, giving the exchange integral for GdIIIJ(Cu-Gd) = -1.52cm-1. This indicated a weak antiferromagnetic interaction between the CuII and CdIII ions.